When a motor vehicle is turning, the driver and passengers of the vehicle experience centrifugal forces due to the lateral acceleration of the vehicle. The sensation experienced by the driver and passengers is a lateral force in the lateral direction opposite the direction in which the vehicle is turning.
A person seated in a car, for example, may attempt to counteract this lateral force by bracing himself against parts of the vehicle during turning, such as the inside of a door or a central console. In addition, car seats generally include structures to provide a certain degree of lateral support.
In a straddle-type vehicle, such as a snowmobile, an ATV or a three-wheeled road vehicle, the straddle-type seat generally provides little or no lateral support to the rider seated thereon, and there are generally no side structures such as doors or consoles against which a rider can brace himself during turning. In addition, the rider may desire to lean into turns, even if the vehicle itself does not lean when turning. A structure providing lateral support on a straddle-type vehicle would obstruct the rider's leaning, thereby reducing his enjoyment from operating the vehicle.
As a result, a rider of a straddle-type vehicle that does not lean when turning must attempt to counterbalance the centrifugal forces by shifting his weight and gripping whatever structures are available to be gripped on the vehicle. This can be tiring for the rider, particularly on long trips and particularly for a passenger who does not have handlebars to grip and can only brace himself by gripping side hand grips provided on the vehicle or holding on to the driver.
Therefore, there is a need for a straddle-type vehicle that provides lateral support for a passenger without interfering with the passenger's enjoyment of riding the vehicle.